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Extensive research works have been carried out over the past few decades in the development of simulation tools to predict the thermal performance of buildings. These validated tools have been used in the design of the building and its components. However, limited simulation tools have been developed for modeling of district energy systems, which can potentially be a very laborious and time-consuming process. Besides many associated limitations, providing a realistic demand profile of the district energy systems is not a straightforward task due to high number of parameters involved in predicting a detail demand profile. This paper reports the development of a simplified model for predicting the thermal demand profile of a district heating system. The paper describes the method used to develop two types of simplified models to predict the thermal load of a variety of buildings (residential, office, attached, detached, etc.). The predictions were also compared with those made by the detailed simulation models. The simplified model was then utilized to predict the energy demand of a variety of districts types (residential, commercial or mix), and its prediction accuracy was compared with those made by detailed model: good agreement was observed between the results. [ABSTRACT FROM AUTHOR]

The selection of a thermal comfort model for establishing indoor optimal hygrothermal conditions during the hot period has a major impact on energy consumption of Net Zero Energy Buildings in hot climates. The objective of this paper is to compare the influence of using different thermal comfort models for zero energy buildings in hot climates. The paper compares the impact of applying Fanger's model, Givoni's model, the ASHRAE 55 adaptive comfort model and the EN 15251 adaptive comfort model on energy consumption and comfort performance. Using both the building performance simulation tools ZEBO and EnergyPlus for energy simulation, an existing prototype of a residential apartment module is used to evaluate energy performance and thermal comfort in two parametric series. The first one is the result of coupling natural ventilation and mechanical cooling and the second one is guided coupling natural ventilation, mechanical cooling and ceiling fans. This study shows that the percentage of energy consumption difference meeting the comfort criteria according to ISO 7730 in comparison to EN 15251, ASHRAE 55 or Givoni's model varied up to 16%, 21% and 24.7%, respectively for the presented case study. More energy savings can be expected for buildings in hot climates with greater cooling demands. [ABSTRACT FROM AUTHOR]

Global warming has drawn great attention in recent years because of its large impact on many aspects of the environment and human activities in buildings. One area directly affected by climate change is the energy consumption for heating and cooling. To quantify the impact, this study used the HadCM3 Global Circulation Model (GCM) to generate weather data for future typical meteorological years, such as 2020, 2050, and 2080, for 15 cities in the U.S. based on three CO 2 emission scenarios. The method was validated by comparing the projected TMY3 data using HadCM3 with the actual TMY3 data. By morphing method, the weather data was downscaled to hourly data for use in building energy simulations by EnergyPlus. Two types of residential buildings and seven types of commercial buildings were simulated for each of the 15 cities. This paper is the first to systematically study the climate change impact on various types of residential and commercial buildings in all seven climate zones in the U.S. through EnergyPlus simulations and provide weighted averaged results for national-wide building stock. We also identified geographical dependency of the impact of climate change on future energy uses. There would be a net increase in source energy consumption by the 2080s for climate zones 1–4 and net decrease in climate zones 6–7 based on the HadCM3 weather projection. Furthermore, this paper investigated natural ventilation performance in San Francisco, San Diego, and Seattle with improved natural ventilation model. We found that by the 2080s passive cooling would not be suitable for San Diego because of global warming, but it would still be acceptable for San Francisco and Seattle. [ABSTRACT FROM AUTHOR]

Energy retrofit of existing buildings was highlighted as an efficient massive action to decrease energy consumption and emissions of greenhouse gases. But, detecting the optimal retrofit strategies for groups of buildings is nowadays a highly complex problem. Their energy consumptions are influenced by building-related factors (climate, building envelope, building services and systems) and by user-related ones (building operation and maintenance, occupant behavior, and indoor environmental quality). Detecting the contributions of each factor and grouping buildings with similarities –in order to establish similar retrofit strategies – are the main issues that can be faced by statistical multivariate methods. In this paper, we present a new and broader view to propose retrofit strategies adapted to a climate change scenario and analyzed from the economic and energy-poverty points of view, by using multivariate and clustering techniques that include building-related and user-related metrics influencing the energy consumption of groups of buildings. A group of 10 single-family houses in Argentina were selected as a case-study. The contributions of eleven building-related driving metrics and four user-related ones to the energy consumption were analyzed. Then, the more representative house of the cluster was selected for a retrofit analysis for current weather conditions and for future weather under a climate change scenario. The analysis also included an economic assessment in relation to the energy poverty. The higher CV values found in the user-related metrics highlight the influence of occupants in the energy consumption that can result in huge gaps between real and predicted energy performance of buildings. This holistic study contributes to reveal the internal structure of energy consumption and to generate useful knowledge about energy retrofit of the built environment in cities, particularly for those householders which are more susceptible to suffer the adverse effects of energy poverty and climate change. [ABSTRACT FROM AUTHOR]

Energy consumption has dramatically increased in buildings over the past decade due to population growth, more time spent indoors, increased demand for building functions and indoor environmental quality, and global climate change. Building energy use currently accounts for over 40% of total primary energy consumption in the U.S. and E.U. Nevertheless, significant energy savings can be achieved in buildings if they are properly designed, constructed and operated. For this reason, building energy efficiency can provide key solutions to energy shortages, carbon emissions and their serious threat to our living environment. This paper offers a brief overview of building energy-consumption situations, relevant energy-saving approaches, and the influence of global climate change. Building energy-consumption situations based on data derived from international energy reports are initially compared between the U.S., China and the E.U. Both similarities and differences are found in aspects of building energy end-uses and final energy fuel-types among these top three building energy consumers. We then introduce the current concept of the zero-energy building (ZEB). State-of-the-art approaches for ZEB technologies are summarized in three categories: passive energy-saving technologies, energy-efficient building service systems and renewable energy production technologies. The feasibility of these technologies is reviewed. In addition, we briefly discuss the influence of global climate change on the evolution of building energy use in the future. We find that climate change significantly impacts building energy performance, particularly in space heating and cooling. Improvements on building envelope and ventilation can play an important role in reducing space heating and cooling consumption levels. We also provide some suggestions for further developing ZEBs. [ABSTRACT FROM AUTHOR]

Cooling of buildings currently represents a considerable fraction of the total energy consumption in the world. Global and local climate change in combination with the projected population increase and economic development is expected to increase tremendously the future cooling energy demand of buildings and make it the dominant energy component. The present paper aims to present and discuss the details of the framework which defines the present and future cooling energy consumption of the building sector. The more recent quantitative and qualitative data concerning the penetration of air conditioning around the world are presented and analyzed. The main technological, economic, environmental and social drivers that determine the market penetration of air conditioning are identified and their impact is investigated. The potential future evolution of the main parameters that define the cooling energy consumption and in particular climate change, the population increase, income growth, potential technological improvements and the main socioeconomic drivers are investigated and existing forecasts are presented. Proposed methodologies to predict the future cooling energy consumption of the building sector are reported and discussed, while existing estimates and predictions regarding the future cooling energy consumption of individual buildings as well as of the total building sector are documented, evaluated and analyzed. Based on the explored inputs and forecasts, a model to predict the future cooling energy consumption of both the residential and commercial sector is developed. Three scenarios based on low, average and high future development, compared to the current development, are created and the range of the expected cooling energy demand in 2050 is predicted under various boundary assumptions. It is calculated that the average cooling energy demand of the residential and commercial buildings in 2050, will increase up to 750% and 275% respectively. [ABSTRACT FROM AUTHOR]

In order to deliver the European energy and climate objectives to 2050, significant changes are essential in the building sector, especially regarding the existing stock. Indeed, there is a huge potential for action, also regarding historic buildings. In this regard, today the question is: how to combine the building protection requirements and the application of energy efficiency measures? This paper tries to answer, evaluating if the refurbishment of historic architectures, in order to achieve very low energy need, is possible and economically feasible. More in detail, the applicability of the cost-optimal methodology (EPBD Recast 2010/31/EU) for historic buildings is discussed, by adopting the macroeconomic perspective, in order to take into account of the energy, environmental and economic impacts of about 60 packages of energy efficiency measures. The study is aimed to introduce a methodological approach to define reference buildings for historic architectures, through in-situ investigation of structural and energy peculiarities and, as real case study, the refurbishment of an Italian building of the XV century is presented. Moreover, guidelines are proposed to properly select energy efficiency measures, according to a point of view of cost-optimality. Conservation, aesthetical requirements, structural and energy issues are considered, as well as the incidence of all economic factors. [ABSTRACT FROM AUTHOR]

Abstract: A major focus of existing literature on energy conservation is the modelling and quantification of energy savings and the corresponding carbon dioxide emissions from lightings. While many studies have established theoretical frameworks concerning these issues, very little documentation exists relating to energy savings and emission levels in students’ hostels. This paper considers the lighting efficiency improvement of four University of Lagos halls of residence for the purpose of quantifying energy saving and the minimization of carbon dioxide that can be made. Compact fluorescent lamps are considered alternatives to the current primary usage of conventional fluorescent and incandescent bulbs. The existing electricity consumption data obtained from energy audit are used in combination with conversion factors to estimate the annual CO2 contributed to the atmosphere by lighting in each of the buildings. The result of the study shows that over 45% reduction in carbon dioxide emission can be achieved. There is a lot individuals can do to reduce the emissions, for example, using energy saving appliances, turning off appliances when not in use, less use of fossil fuels, are simple measures that can be adopted to reduce annual carbon footprint, improve economic growth, enhance environment, health and save the planet. [Copyright &y& Elsevier]

Abstract: Energy efficiency in buildings is essential for economic, social, and environmental reasons. Under current European legislation, buildings have to be certified with an energy efficiency index. To provide a fair comparison of the energy performance in buildings we need a global and unified representation. In this paper we propose the Energy Efficiency Ontology (EEOnt) to provide a foundation upon which this requirement can be built. EEOnt extends the applicability of other ontological models of buildings incorporating energy efficiency data and knowledge that can be calculated with high spatial and temporal resolution in what we call an Energy Efficiency Landscape (EELB). These EELB''s provide significant information which allows a detailed diagnosis of the energy efficiency within the building. Consequently, EEOnt is capable of representing buildings and energy efficiency in a unified way. Furthermore, it supplies a tool for managing the energy efficiency in buildings and constructing national inventories. These two features link the global and particular needs of governments and users, thus becoming key to both improve the energy efficiency in buildings and to implement viable certification schemes. [Copyright &y& Elsevier]

Abstract: Energy consumption in buildings is heavily affected by climate change. It causes significant variations of the outdoor design conditions, cooling and heating loads. In this paper, a total of 40 years (1967–2006) of hourly temperature data were considered in four decades and outdoor design conditions for each decade were calculated. It was found that wet-bulb temperature (WBT) has increased by 3.28°C during the mentioned period, which impacts on design and selection of the cooling equipment. The results show that cooling hours is projected to increase around 15% over the whole 1967–2006 period. The most important result found in this study is the inability of direct evaporative cooling (DEC) systems in preparing comfort condition after 1997, whereas these systems provided thermal comfort in Tehran''s buildings from 1967 to 1996. The prediction of climate change impacts on the outdoor design conditions and cooling systems performance until 2020 demonstrates dry bulb temperature (DBT) and WBT increase 1.05°C and 2.42°C respectively. Hence, indirect–direct evaporative cooling systems (IDEC) may not be responsible for the years after 2016. Besides, the additional energy for absorption and vapor compression (VC) cooling systems will grow quickly in the future. [Copyright &y& Elsevier]

Abstract: The Kyoto protocol binded the developed countries to reduce the greenhouse gas emissions at least by 5% by 2008–2012 in order to tackle global warming and climate change. Some of the measures of the governments to achieve this goal are to promote new buildings construction and to retrofit existing buildings while satisfying low energy criteria. This means improving energy efficiency of buildings and energy systems, developing sustainable building concepts and promoting renewable energy sources. The design of a low energy building requires parametric studies via simulation tools in order to optimize the design of the building envelope and HVAC systems. These studies are often complex and time consuming due to a large number of parameters to consider. Hence, this paper aims to set up a methodology that simplifies parametrical studies during the design process of a low energy building. The methodology is based on the Design of Experiments (DOE) method which is a statistical method widely used in industry to perform parametric studies that reduces the required number of experiments. [Copyright &y& Elsevier]

Abstract: Simulation packages for predicting building performance in terms of energy and comfort are becoming increasingly important in the planning process. However, current industry standard weather files for building simulation are not suited to the assessment of the potential impacts of a changing climate, in particular summer overheating risks. In addition, no bespoke climate change weather files are readily available that can be loaded directly into environmental simulation software. This paper describes the integration of future UK climate scenarios into the widely used Typical Meteorological Year (TMY2) and EnergyPlus/ESP-r Weather (EPW) file formats and demonstrates the importance of climate change analysis through a case study example. The ‘morphing’ methodology published by the Chartered Institution of Building Services Engineers (CIBSE) is utilised as a baseline for transforming current CIBSE Test Reference Years (TRY) and Design Summer Years (DSY) into climate change weather years. A tool is presented that allows generation of TMY2/EPW files from this ‘morphed’ data and addresses the requirements related to solar irradiation, temperature, humidity and daylighting beyond the parameters provided by CIBSE weather years. Simulations of a case study building highlight the potential impact of climate change on future summer overheating hours inside naturally ventilated buildings. [Copyright &y& Elsevier]